如何在 C++ 中完全释放 cv::Mat 的内存

Question

当我尝试创建 cv::Mat 并在之后释放它时（下面的代码），我仍然有（根据 valgrind）内存泄漏，每个像素大约 1 字节。

有谁知道如何正确释放 cv::Mat 的内存？

感谢回答:)

代码：

int main(int argc, char** argv)
{
  cv::Mat* matrx = new cv::Mat(1000,1000,CV_8UC1,0.);
  matrx->release();
  delete matrx;
  return 0;
}

瓦尔格林德：

[...]
==29420==    1,000,028 bytes in 1 blocks are definitely lost in loss record 372 of 372
==29420==    at 0x4C2AB80: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==29420==    by 0x5438877: cv::fastMalloc(unsigned long) (in /usr/lib/x86_64-linux-gnu/libopencv_core.so.2.4.8)
==29420==    by 0x536FE2A: cv::Mat::create(int, int const*, int) (in /usr/lib/x86_64-linux-gnu/libopencv_core.so.2.4.8)
==29420==    by 0x426FB5: cv::Mat::create(int, int, int) (mat.inl.hpp:663)
==29420==    by 0x426ECD: cv::Mat::Mat(int, int, int, cv::Scalar_<double> const&) (mat.inl.hpp:347)
==29420==    by 0x425A09: main (main.cpp:18)
==29420== 
==29420== LEAK SUMMARY:
==29420==    definitely lost: 1,000,028 bytes in 1 blocks
==29420==    indirectly lost: 0 bytes in 0 blocks
==29420==      possibly lost: 5,072 bytes in 95 blocks
==29420==    still reachable: 304,758 bytes in 1,348 blocks
==29420==         suppressed: 0 bytes in 0 blocks
[...]

Answer 1

来自 opencv github 的反馈似乎很明确：您使用 OpenCV 3.x 编译，但在运行时使用 OpenCV 2.4.8。由于它们不是二进制兼容的，因此无法正确释放 cv::Mat。让我们将您的 LD_LIBRARY_PATH 导出到用于编译的 OpenCV OCV_DIST/lib 3.x。

请注意，如果您 delete 指针，您甚至不需要 release() 之前。

Answer 2

从文档页面引用以下内容：(http://docs.opencv.org/2.4.9/modules/core/doc/basic_structures.html#mat-release):

无效Mat::release() 该方法递减与矩阵数据相关联的参考计数器。当引用计数器达到 0 时，矩阵数据被释放，数据和引用计数器指针设置为 NULL。

上面的意思是当你做"delete matrx;"时你试图删除一个已经指向NULL的内存区域，这会产生一个运行-time错误。

如何在 C++ 中完全释放 cv::Mat 的内存

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